Signatures produced from printing presses, such as those for newspapers, periodicals, and catalogs are typically cut from a moving web of printed material traversed through the printing press. After the cut, the signature is typically folded at least once to produce the desired configuration for the end product.
The printing press industry has typically employed one of two mechanisms for creating a fold within a signature cut from a moving web. One of the known mechanisms for creating the fold is referred to as a rotary folder or couple, wherein a pair of second fold rollers are positioned proximate a folding cylinder with a gap or nip being provided between the second fold rollers. The web of material is wrapped around the folding cylinder and a folding blade is adapted to extend from the folding cylinder in a position corresponding to the nip. The folding blade is typically mounted to a spider assembly used to appropriately time the extension of the folding blade. When a folding blade extends from the folding cylinder, the folding blade extends into the nip, pushing the signature cut from the web into the nip. The second fold rollers, which rotate away from the folding cylinder, complete the fold in the signature initiated by the folding blade, and process the folded signature on to a delivery system including such things as delivery flies and conveyor belts.
Another known type of folding couple is referred to as a jaw folder wherein a jaw cylinder is positioned proximate the folding cylinder with a plurality of jaws or clamp assemblies positioned around the periphery of the jaw cylinder. The timing of the rotating jaw cylinder is coordinated with the rotation and extension of the folding blade from the folding cylinder such that when the folding blade extends from the folding cylinder, the folding blade extends into one of the jaws or clamp assemblies on the jaw cylinder. This in turn pushes the fold of the signature into the jaw or clamp to complete the fold. The jaw is then released to allow the folded signature to be transported away by a delivery system. Examples of such jaw cylinders are disclosed in U.S. Pat. Nos. 5,226,871, 5,522,586, and 5,797,319, the disclosures of each being herein incorporated by reference.
While such systems continue to be used, certain production criteria necessitate the need for one or the other type of folding couple. For example, rotary folders have proven to be extremely rugged and durable and thus are often preferred by facilities wherein it is desirable to produce a large quantity of product on a daily basis, such as with a newspaper. However, jaw folders have proven to be more accurate and to result in minimized marking on the signatures and thus are more desirable in situations wherein extremely high quality and accuracy are at a premium, such as with magazines and catalogs.
Some printing presses are equipped with both mechanisms. However, such presses are relatively expensive in that, among other things, two separate folding couples need to be provided. This includes additional frames, drive shafts, drive gearing, delivery flies, and conveyors. In addition, since the hardware for both the rotary folder and jaw folder are provided on the same press, regardless of which is being used, the mechanics of the resulting press are tightly grouped, with little access room being provided in the press for maintenance and the like.